1. Field of Invention
The present invention relates to an apparatus of an organic light emitting diode (OLED) which provides good resistance to water vapor and oxygen and a packaging method of forming the apparatus.
2. Description of Related Art
Recently, a flat panel display has been the focus display as the technology is advanced. In particular, an organic electro-luminescence display has the advantages of self-luminescence, no viewing angle restriction, low power consumption, simple manufacturing process, low production cost, low operation temperature, fast responsive speed and full-colors. Accordingly, the organic electro-luminescence display has great potential for applications and becomes the mainstream for the next generation displays. The organic electro-luminescent display utilizes a self-luminescence feature of the organic functional material in the OLED device for providing display purposes. The OLED device is typically comprised of a pair of electrodes and the organic functional layer. As the current passes through the area between the anode and the cathode, the electrons and the holes in the organic functional layer are combined to produce excitons, thus allowing the organic functional layer, according to its material characteristics, to produce different light emitting mechanisms for different colors.
The organic functional material and the anode of the OLED device react with water vapor and oxygen in the air easily, and thus the performance of the device is degraded. Therefore, it is fairly important to remove water vapor thoroughly so as to enhance the durability of the organic light emitting panel. During the manufacturing process of the OLED, a deposition process is usually performed under vacuum, and the OLED is sealed with a packaging method. The manufacturing process of the OLED device is in a high-vacuum environment. However, it is required to change the environment from high vacuum to low water vapor and oxygen state when the top cover packaging process is performed. The transition state allows few water vapor and oxygen to adhere to the OLED and the lifetime of the device is accordingly reduced.
Getter is applied to the packaging technology using a hard substrate (such as a glass) for reducing the effect of water vapor and oxygen on the device. However, no space for the getter is present in the flexible OLED device structure, and such method cannot assure that the OLED is not affected by water vapor and oxygen. Therefore, another packaging technology using a film is developed to replace the packaging technology using the getter.
Generally speaking, the film packaging process without using the getter is require to directly perform after the anode of the OLED is deposited by evaporation. Accordingly, the process is limited to be conducted at low temperature and with low electric power, and thus a conventional chemical vapor deposition process or a sputtering process cannot be applied to the film packaging.
The U.S. Pat. No. 7,121,912 proposed a treatment method of the anode of a OLED, in which the fabricated OLED device is put in the ozone environment and heated to the temperature less than 100° C. for 30 minutes when the packaging process is performed.
As described above, the packaging technology has a great effect on the lifetime and the performance of the OLED device. Therefore, how to use the film packaging to isolate the OLED from the external environment so as to increase the lifetime of the device has been one of the main topics in the industry.